| gypsum | <chemical> A mineral consisting of the hydrous sulphate of lime (calcium). When calcined, it forms plaster of Paris. Selenite is a transparent, crystalline variety; alabaster, a fine, white, massive variety. Origin: L. Gypsum, Gr.; cf. Ar. Jibs plaster, mortar, Per. Jabsn lime. Source: Websters Dictionary (01 Mar 1998) |
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